DTC C1254/54: Pressure Switch Circuit: Procedure

1. Check the Data List for proper functioning of the hydraulic brake booster pressure switch (PH and PL).
   1. Depress the brake pedal more than 40 times with the ignition switch OFF, and then turn the ignition switch ON and check the pressure switch (PH and PL) condition.
      ABS/VSC/TRAC
      
      

      Tester Display	Measurement Item / Range	Normal Condition	Diagnostic Note
      High Hydraulic Boost SW	High Hydraulic brake boost pressure / ON or OFF	ON: High pressure OFF: Low pressure	-
      Low Hydraulic Boost SW	Low Hydraulic brake boost pressure / ON or OFF	ON: High pressure OFF: Low pressure	-

      HINT: 

      When pressure in the power supply system is released, the brake pedal becomes easier to depress.

      OK

      "OFF" turns to "ON".

OK → REPLACE SKID CONTROL ECU 

NG: Go to next step 

Fig 1: Checking Brake Booster Pressure Switch (PH)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Disconnect the B1 connector from the brake actuator.
2. With the ignition switch OFF, depress the brake pedal more than 40 times to decrease the accumulator pressure.

   HINT: 

   When pressure in the power supply system is released, the brake pedal becomes easier to depress.

3. Measure the resistance between terminals PH and PHG of the brake actuator connector.

   Standard resistance

   0.9 to 1.1 kΩ

4. Connect the B1 connector to the brake actuator.
5. Disconnect the B1 connector after the ignition switch has been ON and the pump motor has stopped.
6. Measure the resistance between terminals PH and PHG of the brake actuator.

   Standard resistance

   0 Ω

   HINT: 

   After the inspection, connect the connector and clear the DTC. Refer to DTC CHECK / CLEAR .

NG → REPLACE BRAKE ACTUATOR 

OK: Go to next step 

Fig 2: Checking Brake Booster Pressure Switch (PL)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Disconnect the B2 connector from the brake actuator.
2. With the ignition switch OFF, depress the brake pedal more than 40 times to decrease the accumulator pressure.

   HINT: 

   When pressure in the power supply system is released, the brake pedal becomes easier to depress.

3. Measure the resistance between terminals PL and PLG of the brake actuator connector.

   Standard resistance

   5.1 to 6.3 kΩ

4. Connect the B2 connector to the brake actuator.
5. Disconnect the B2 connector after the ignition switch has been ON and the pump motor has stopped.
6. Measure the resistance between terminals PL and PLG of the brake actuator.

   Standard resistance

   1.0 kΩ

   HINT: 

   After the inspection, connect the connector and clear the DTC. Refer to DTC CHECK / CLEAR .

NG → REPLACE BRAKE ACTUATOR 

OK: Go to next step 

Fig 3: Checking Wire Harness (Brake Actuator - Skid Control ECU And Body Ground)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Disconnect the B1 and B2 actuator connectors.
2. Disconnect the S5 and S8 ECU connectors.
3. Measure the resistance of the wire harness side connectors.

   Standard resistance

   Tester Connection	Specified Condition
   B2-4 (PL) - S5-9 (PL)	Below 1 Ω
   B1-3 (PH) - S8-11 (PH)	Below 1 Ω
   B1-5 (PHG) - Body ground	Below 1 Ω
   B2-2 (PLG) - Body ground	Below 1 Ω

NG → REPAIR OR REPLACE HARNESS AND CONNECTOR 

OK → REPLACE SKID CONTROL ECU